The appeal always faced narrow odds for success at the Denver-based appellate court. The court, which is one rung below the U.S. Supreme Court, has decided only about one in four death-penalty appeals in favor of the inmate over the past decade, according to a Denver Post analysis of court decisions. Of the 42 death-row inmates in that span who have so far had their appeals ruled on by the court, 25 have since been executed. Nine more remain on death row awaiting execution.

The ratio is typical of what University of Oklahoma law professor Randall Coyne* says is the even-handed reputation of the court on death-penalty matters. The 10th Circuit, Coyne said, isn’t seen as a rubber stamp for deaths sentences, but it also isn’t a frequent blocker of them.

“The 10th Circuit’s reputation is that of a moderate court,” Coyne, an expert on capital punishment, said. “They tend to be middle of the road.”

Dunlap’s appeal — which was argued last month before a three-judge panel of the court — was unique in the 10th Circuit only in its origin. It had been 16 years since the 10th Circuit last heard a death-penalty appeal by a Colorado inmate.

But death-penalty cases are fairly commonplace at the court because its jurisdiction also includes Oklahoma, which has executed more people per capita than any other state in the modern era of capital punishment, according to the Death Penalty Information Center. The same week in March when the 10th Circuit heard Dunlap’s appeal, court judges also heard two other death-penalty appeals. Judges heard two more later in the month, and another is scheduled to be heard this month.

Such a case load means 10th Circuit judges are well-versed on death-penalty issues.

“These judges are very well prepared,” said Oklahoma attorney Jim Rowan, who has represented death-row inmates before the court. “You better know your stuff in front of them.”

Since 2002, death-row inmates have asked the 10th Circuit to spare their lives 88 times in filings known as habeas corpus appeals, according to the Denver Post analysis. In the 51 cases in which the court has issued a ruling — some inmates have had multiple appeals decided — the 10th Circuit has declined to block execution 33 times. In another 13 cases, the court granted the appeals, at least temporarily blocking execution and in several cases giving the inmates new sentencing hearings or trials. Five cases addressed procedural issues that did not decide the fate of the execution.

Coyne said the judges are restricted in how often they can overturn sentences by a 1996 law known as the Antiterrorism and Effective Death Penalty Act. The law says federal appellate judges can only overturn state court rulings if they find the state court was unreasonably wrong and not just merely in error.

“It used to be,” Coyne said, “federal habeas was the most likely venue to win in.”

Even still, a 10th Circuit decision is not the last word on an execution. In the last decade, several inmates from Oklahoma who have lost an appeal at the court have subsequently avoided execution through another appeal or commutation by the governor. An inmate who won a new sentencing hearing from the 10th Circuit has since been re-sentenced to death.

Dunlap is Colorado’s longest-serving death-row inmate. He was sentenced to die in 1996 for killing four people more than two years earlier at an Aurora Chuck E. Cheese restaurant.

The 10th Circuit usually takes several months to issue a ruling after hearing arguments on an appeal. For instance, it took 10th Circuit judges about 6 months to issue a ruling on the appeal of Gary Davis, the last inmate Colorado executed. Davis was executed about a year after the 10th Circuit’s ruling in his case, following a U.S. Supreme Court refusal to hear his appeal. Davis decided not to pursue further appeals after that defeat.